Chemistry 121 Full Name___________________________
Final Exam, Dr. Price
1. Ca
y out the conversions below. Be sure to show your work and report your answers rounded to the co
ect number of significant figures with co
ect units.
a. (2 points) How many mL (nilliliters) are there in 250.0 L (liters)? Show your work.
. (2 points) What is 231.5 Kelvin in °C (273.15K = 0.00ºC)? Show your work.
2. (3 points) Use your model kit to build and upload a photo of the following molecules and answer the following:
Formula
Lewis Structure
Shape (linear, bent, triangular, pyramid, or tetrahedral) and bond angles
Polar or
Non-Polar Molecule, Include the dipole a
ow if one exists.
PH3
CH2Cl2
3. (1 points) Draw two molecules of ethanol (CH3CH2OH) and use a dashed line to show the Hydrogen attraction (also called the H-bond) between two molecules.
4. (1 points) Draw two molecules of ethanol (CH3CH2OH) and use a dashed line to show the Dipole-Dipole (not the H-bond) attraction between the two molecules.
5. (4 points) Which molecular shapes are always polar? Name them and give an example of each.
6. (6 points) Methane is the main component of so-called natural gas. 7.00 grams of O2 react with 7.00 grams of CH4 according to the following reaction:
CH4 + 2O2 CO2 + 2H2O H = -803 kJ
a. What are the health and climate dangers of burning methane (so-called natural gas)?
. Is the reaction exothermic or endothermic? ______________________
c. How many moles of CO2 are produced by the reaction of 7.00 grams of O2 react with7.00 grams of CH4? (hint: this is a limiting reactant problem)
d. How many molecules of CO2 are produced by the reaction of 7.00 grams of O2 react with 7.00 grams of CH4?
7. (2 points) Name the following acids and bases. Also label them as strong acid, weak acid, strong base, or weak base.
NaOH CH3COOH HCl NH3
8. (3 points) Label the following salts as acidic, basic or neutral. If acidic or basic, circle the component that makes the salt acidic or basic.
NH4Cl NaCl NaF
9. (1 points) Does a 1.00 M solution of HCl have a higher, lower, or equal pH compared to a 1.00M solution of HF? Explain why.
10. (1 points) Describe the intermolecular forces that
eak down the coronavirus when you wash your hands.
11. (1 points) What is a buffer and how would you make one?
12. (2 points) Write out the following balanced nuclear reaction:
a. Uranium-238 (alpha decay)
XXXXXXXXXXpoints) What is wrong with the following atomic symbol? Explain and suggest a co
ection.
14
7
C
14. (3 points) Describe ca
on dating. What is it and how does it work? Describe the chemistry.
15. (5 points) Why do people check for Radon (a Nobel gas) in their home? (include the chemistry as you learned in lecture in your explanation)